The A3977xED and A3977xLP are complete microstepping motor drivers with built-in translators. They are designed to operate bipolar stepper motors in full-, half-, quarter-, and eighth-step modes, with output drive capability of 35 V and ±2.5 A. The A3977 includes a fixed off-time current regulator that has the ability to operate in slow-, fast-, or mixed-decay modes. This current- decay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation. The translator is the key to the easy implementation of the A3977. By simply inputting one pulse on the STEP input the motor will take one step (full, half, quarter, or eighth depending on two logic inputs). There are no phase detection, so the motor can be used with or without a Hall sensor driver. The A3977 can be connected to an external microcontroller via a separate I2C port to implement more advanced features.
The A3977xED (44‑pin PLCC) and A3977xLP (28‑pin TSSOP) are complete microstepping motor drivers with built‑in translator, designed for bipolar stepper motors in full‑, half‑, quarter‑, and eighth‑step modes. They provide up to 35 V load supply voltage and ±2.5 A output current, with low on‑resistance MOSFETs and internal synchronous rectification to reduce power dissipation.
The devices include internal protection such as thermal shutdown, under‑voltage lockout (UVLO) and crossover‑current protection. They operate over a wide temperature range (‑40 °C to +125 °C for the K‑variant) and are supplied in lead‑free versions. Detailed electrical characteristics, timing requirements, layout recommendations, and pin definitions are provided for designers.
| Load Supply Voltage (VBB) max | 35 V |
|---|---|
| Output Current (IOUT) max | ±2.5 A |
| Operating Temperature Range (TA) – A3977Kx | -40 °C to +125 °C |
| Junction Temperature max | +150 °C |
| Thermal Shutdown Temperature | 165 °C |
| Package Thermal Resistance (θJA) – LP | 28 °C/W |
| Package Thermal Resistance (θJA) – ED | 32 °C/W |
The driver can operate with a load supply voltage up to 35 V.
It supports full‑step, half‑step, quarter‑step, and eighth‑step modes.
The device includes thermal shutdown, under‑voltage lockout (UVLO), and crossover‑current protection.